Azimuth determination method



April 7, 1936. J. E. OWEN AZIMUTH DETERMINATION METHOL Filed Feb. 2:5, 19:55

2 Sheets-Sheet l IV I ATTORNEYS.

p l 7. 36 J. E. OWEN 2,036,824

AZ IMUTH DETERMINATION METHOD Fil ed Feb. 23, 1935 2 Sheets-Sheet 2 w I INVENTOR.

ATTORNEYS.

"UNITED STATES PATENT OFFICE 2,036,824 AZIMUTH DETERMINATION METHOD John E. Owen, Tulsa, Okla., asslgnor to Geophysical Research Corporation, New York, N. 1., a corporation of New Jersey Application February 23, 1935, Serial No.'7,i69

18 Claims. (Cl. 18 10.5)

This invention relates to the determination of ing film F of the response of each wave detector. the azimuth of an instrument arranged below the Any suitable means may be provided to make the earths surface, as for example, in a bore hole recording channels of equal sensitivity. or in a lake or other body of water. In the practice of the method, seismic waves An object of this invention is an azimuth deare artificially produced at a point 8 near the 5 termination method and means which utilizes earth's surface, preferably by detonation of a the directional characteristics of artificial seismic charge of dynamite. Waves travel from the waves. source S to the instrument D along the path P According to the invention, the instrument of and are received by the detectors Di and D2 and which the azimuth is to be determined, is equipped recorded on the film F. 10

with two or more angularly related seismic wave Preferably, the wave source S is arranged sufdetectors, each of which has only one degree of ficiently distant from the mouth of the bore hole freedom and hence responds only to the com that the wave arriving at the instrument in the ponent of motion along its axis. Artificial bore hole is traveling approximately horizontally.

ls seismic waves are produced at a point on the The curved path that gives the approximately earths surface and records are made of the horizontal wave results fromanincrease in velocresponse of the detectors. By comparison of the .ity with depth which normally occurs within the response records of the detectors, determination top few thousand feet of the earth's surface. may be made of the azimuth of the instrument. Fig. 3 illustrates a typical record obtained by- 59 Other objects, novel features and advantages the method above described and presents a set w of this invention will become apparent from the of conditions by which may be determined the following specification and accompanying drawazimuth of the instrument D. ings, wherein: Assume that the maximum amplitude in the Fig. 1 is a diagrammatic view of the apparatus record made by detector D1 is five units and by as used in practicing the invention; D: is two units. Hence, the anglebetween the g5 Fig. 2 is an enlarged view of the instrument axis of D1 and the path of the wave is: with wave detectors attached; 2 I I 5 o Fi .2aisaviewsimllartoFi o amodificaare not --22 t g h 7 42 i so Figs. 3, 4, 5 and 6 illustraterecords of the rewhile the angle .between the axle of D2 and the so spouse of the several detectors to the seismic wave is: waves, and l g 0 Figs. '7 and 8 illustrate orientation graphs. T

Referring now to Figs. 1 and 2, B designates a s5 bore hole in the earth in which is arranged an Since-the P08119101! f the Wave Source 5 end instrument 1 the azimuth of which is t be hence the direction of travel of the recorded wave termined. As shown in Fig. 2, the instrument D is w the azimuth o D may be det d- 1 equipped t t v detectors and D2, Arbitrarily assuming the axis of reference in the each of which has one degree of freedom and instrument D as the axis of the detectorDl and hence responds only to the component of mo-' assuming the source S to be located due north of 40 tion along its axis. These detectors preferably he e hole. the azimuth of 1D 18 88 h in f are arranged at right angles to each other and 8- preferably are so mounted that they always re- 4 illustrates. a recm'd made with D occumain horizontal. Any suitable means (not w s the same position as for i u with.

shown) ma be rovided for maintaining th thesource 8 due east of the bore hole. It is to 45 tectors inh rlzo tal position. be ed h t w the amplitude of D: has in- The wave detectors are of any of t w creased and that of Dl has decreased and re known types which translate mechanical vibraversed its directiona y, 1sepresents tions into electrical vibrations and are connected the case in which the some heapedhhe through the cable C by'conductors Cl and G2 with south the hole and 6 the so jampliflers A1 and A2. The outputs of the amplih in which 5 is located h west e flers are impressed upon the galvanometers G1 hele- These Illustration-tare ven to show how and which are used in connection t t the invention utilizes both the amplitudes and light source L1 and lens In to effect photographic "the directions of the recorded waves. It is to registration in separate channels on the movbe noted that the absolute, amplitudes of he recorded waves are of no significance as the angle is determined by the relative amplitude of the recorded waves.

The procedure just described is predicated upon equal sensitivity of the two recording channels. However, the azimuth of the instrument may be determined according to the method even though the predicated condition does not exist. Assume for convenience, that when the point S is due north of the bore hole, it has been found that the response of D1 measures plus six units and the response of D2 measures plus three units and that with S due east of the bore hole, it is found that the response of D1 measures minus two units and the response of D2 measures plus five units. Suflicient data are available from these records to determine the azimuth of D.

Let 01 be the angle between the north-south wave path and the axis of D1 and similarly 02 the angle between D2 and said path. Assume that the sensitivity of D2 as previously defined is l/K times that of D1. This gives:

cos i9 1 3K We Let 1 be the angle between the east-west wave path and the axis of D1 and similarly 452 the angle between D2 and the path. This gives:

5K 4W The relations of the angles are as shown in Fig. 8 and cos cos

1 1 Hence,

' cos sin 0 01 2 sm ti -m A150,

v 6 cos 0 m Solving K=0.80

and, 01=24 While it is preferable that the detectors D1 and D; be mounted in such a way that they- Also, while it is preferable that the source S' be placed at a. suflicient distance from the mouth of the bore hole that the wave arriving at D will be practically horizontal, yet the method may be used when this condition is not met. It is possible by use of the theory of wave propagation in a solid to calculate the actual direction of the wave received by the detectors, and make corany construction which will suitably record the response of the detectors.

I claim: 1. The method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth, receiving at the instrument wave components having fixed directional relation to said instrument and individually recording said wave components.

2. The method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth, receiving at the instrument three wave components having fixed directional relation to said instrument and individually recording said wave components.

3. The method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth, receiving at the instrument wave components having right angle relation to each other and fixed directional relation to said instrument and individually recording said wave components.

4. The method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth, receiving at the instrument three wave components having right-angle relation to each other and fixed directional'relation to said instrument and individually recording said wave components.

5. The method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth at a point sufficiently removed from the instrument that the seismic wave reaching the instrument is traveling substantially horizontal, receiving at the instrument wave components having fixed directional relation to said instrument and individually recording said wave components.

6. The method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth at a point sufilciently removed from the instrument that the seismic wave reaching the instrument is traveling substantially horizontal, receiving at' the instrument horizontal wave components having fixed directional relation to said instrument and individually recording said wave components.

7. The method of determining the azimuth ofan instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth at a 'point sufliciently removed from the instrument that the seismic wave reaching the instrument is traveling substantially horizontal, receiving at the instrument wave components having right angle relation to each other and fixed directional relation to said instrument and individually recording said wave components.

8. 'I'he'method of determining the azimuth of an instrument below the earths surface which comprises producing a source of artificial seismic waves in the earth at a point sufficiently removed from the instrument that theseismic wave reaching the instrument is travelingsubstantially horizontal, receiving atthe instrument horizontal wave components having right angle relation to each'other and fixed directional relation to said instrument and individually recording said wave components.

9. The method of determining the azimuth of an instrument below the earth'sv surface which comprises producing a source of artificial seismic waves in the earth, receiving waves by detectors fixed to said instrument and each having one degree of freedom. and individually recording the output of each detector.

, 10L The method of determining the azimuth of an instrument below the earth's surface which comprises producing a source of artificial seismic waves in the earth, receiving waves at said instrument by detectors having a single line response and fixed to saidinstrument with the response lines at right angles, and individually recording the outputs of said detectors.

11. The method of determining the azimuth of an instrument below the earth's surface'which comprises producing a source of artificial seismic waves in the earth, receiving waves by three detectors having single line response and fixed t said instrument'with the response lines at right angles to each other, and individually recording the outputs of said detectors.

12. The method of determining the azimuth of an.instrument below the earth's surface which' comprises producing a source of artificial seismic waves in the earth at a point sufiiciently removed from the instrument that the seismic waves from the instrument that the seismic waves reaching the instrument are traveling substan-' tially horizontally, receiving said waves at said instrument by detectors having single line response and arranged-with their response lines horizontal at right angles to each other, and separately recording the outputs of said detectors.

14. Means for determining the azimuth of an instrument below the earths surface comprising two wave detectors fixed to said instrument and each having one degree of freedom, and means connected to said detector for individually recording the output thereof.

15; Means for determining the azimuth of an instrument below the earth's surface comprising a pair of wave detectors, each having one degree of freedom and'being fixed to said instrument with their corresponding axes mutually perpendicular and means connected to saiddetector for individually recording the outputs thereof.

16. Means for determining the azimuth Oren instrument below the earth's surface comprising freedom and being fixed to'said instrument with their corresponding axes mutually perpendicular, and means connected tosaid detectors for individually recording the outputs thereof. I

7 17. Means for determining the azimuth of an 'instrumentbelow the earth's surface comprising a pair of wave detectors having uni-linear response, said detectors being horizontally at-' tached to said instrument with their response line at right angles to each other, and means connected to said detectors for individually recording the outputs thereof.

18. Means for determining the azimuth of an instrument below the earth's surface comprising a pair of wave detectors having uni-linear response, said wave detectors being horizontally attached to said instrument with, their response lines at right angles to each other, a third wave detector having a uni-linear response and being vertically attached to said instrument, and

means connected to said detectors for individually recording the outputs thereof.

. JOHN E. OWEN.

three wave detectors, each having one degree'of 

